World Aquaculture Adelaide: Special session on regional cooperation for improved biosecurity

Brett Herbert introduces the special session with a presentation on biosecurity and regional cooperation.

Transboundary aquatic animal diseases are one of the major concerns for strengthening of aquatic animal health management capacity in the region. The spread of these diseases demonstrates the vulnerability of the aquaculture industry, as well as the wild fish populations, to disease emergence where impacts have been exacerbated by the lack of preparedness. NACA's Aquatic Animal Health Programme, established in 1998, provides a mechanism for regional governments to coordinate disease preparedness, surveillance and response.

Domestication in livestock industries is the process in which animal populations change in response to the artificial environments of farming production systems. Significant and widespread economic gains have been achieved through genetic improvements made through domestication and selective breeding of commercially farmed shrimp species, particularly Litopenaeus vannamei. Different policies on the translocation of shrimp genetic resources have influenced the approaches to shrimp domestication in different countries. The present paper examines the different approaches.

In early 2013, Vibrio parahaemolyticus was discovered as the causative agent of acute hepatopancreatic necrosis disease (AHPND). Subjecting 4 arbitrarily selected V. parahaemolyticus isolates obtained from a single farm in November 2012 to the previously reported immersion challenge protocol, we confirmed that 3 caused high mortality at different rates accompanied by characteristic lesions of AHPND while 1 caused high mortality without such lesions. Virulence may be determined by mobile genetic elements such as plasmids or bacteriophages.

Tropical shrimp aquaculture is facing a disease crisis that may be propelled by an interaction between management practices that cause inbreeding, and the amplification by inbreeding of susceptibility to disease and other stresses. Broodstock accumulate inbreeding and lose genetic diversity when they experience bottlenecks or are chronically too small. The genetic lock is a practice that leads to inbreeding at farm level. Inbreeding may be amplifying the severity of diseases, including the major current threats.

The emergence and spread of new or previously unknown infectious diseases has had very significant impacts on public health, food security and international trade. Disease emergence is the consequence of environmental and/or sociological changes that disrupt the ecological relationship between pathogens and their natural hosts. Understanding the drivers of disease emergence will help us develop policies and practices that will reduce opportunities for disease emergence in aquaculture and improve prospects of containment.